1. Field
One embodiment of the present invention relates to a method of manufacturing a magnetic recording medium such as a patterned medium.
2. Description of the Related Art
In recent years, in magnetic recording media installed in hard disk drives (HDDs), there is an increasing problem of disturbance of enhancement of track density due to interference between adjacent tracks. In particular, a serious technical subject is reduction of a fringe effect of a write head field.
To solve such a problem, a discrete track recording medium (DTR medium) has been proposed in which recording tracks are physically separated by processing a ferromagnetic layer. The DTR medium can reduce a side erase phenomenon, i.e., erasing information from an adjacent track in writing operation, and a side read phenomenon, i.e., reading out information from an adjacent track in reading operation, making it possible to enhance the track density. Therefore, the DTR medium is expected as a magnetic recording medium capable of providing a high recording density. Similarly, a bit patterned medium (BPM) having a dot-like magnetic pattern is also expected as a magnetic recording medium capable of providing high recording density.
A known method of manufacturing a patterned medium (DTR medium or BPM) comprises forming a hard mask film made of carbon and a resist film on the magnetic recording layer, imprinting a stamper to the resist film to transfer patterns of protrusions and recesses, etching the hard mask using the resist film pattern as a mask to transfer the patterns of protrusions and recesses on the hard mask, and etching the magnetic recording layer using the hard mask pattern as a mask to form patterns of protrusions and recesses on the magnetic recording layer.
Jpn. Pat. Appln. KOKAI Publication Nos. 2005-50468 and 2005-56535 disclose the technique in which etching of the magnetic recording layer and the removing of a hard mask are performed in a same step by using an Ar ion beam etching. However, when the disclosed Ar ion beam etching is used, sufficient effect for magnetically deactivate the magnetic recording layer exposed in the recesses cannot expected. As a result, it is required to etch the magnetic recording layer throughout the thickness thereof for making the recesses of the pattern non-magnetic. In this case, however, considering flying characteristics of the magnetic head when the magnetic recording media is installed in a hard disc drive, a step of filling in the recesses with non-magnetic material is required to attain planarization, resulting in severe decrease of productivity.